U.S. Consular employees sent home from Guangzhou for medical checks as secretary of state, Mike Pompeo, sets up a new investigation.

More US citizens have been evacuated from China, reviving concerns that American government personnel and their families may be the target of “sonic attacks”.

US state department officials said on Wednesday it had sent “a number of individuals” from its consulate in Guangzhou back to the US for “further evaluation and a comprehensive assessment of their symptoms”. Last month, a consulate worker in Guangzhou was found to have suffered a mild brain injury after reporting “abnormal sensations of sound and pressure” from late 2017 through to April 2018.

The department sent a team to Guangzhou in late May to examine other US diplomatic staff and their families.

The US secretary of state, Mike Pompeo, on Tuesday announced the formation of a task force to investigate unexplained health incidents among US government personnel and their families overseas.

China’s foreign minister, Wang Yi, described the incident in May involving the US consulate worker as an “individual case”, and one Beijing hoped would not be “magnified, complicated or even politicised”.